Development of In-line Processing Technologies with Pretreatment for Drawing of Bearing Steel Wire Rods

The pickling and phosphate treatment of bearing steel wire rods is troublesome and the fluctuation in its lubrication capability is large because of the high content of carbon and chrome in the steel as compared with general structural steels. Besides, the acid pickling and phosphate treatment require the treatment of waste water and sludge as anti-pollution measure. The authors studied in-line processing technologies for pretreatment in drawing in order to develop a non-polluting process, using mechanical descaling by shot blasting and water-soluble inorganic coating, together with optimization in drawing conditions. A new manufacturing process which is superior to conventional lubrication for drawing was developed, and the degreasing process using 1.1.1-trichloroethane, known to be pollutant, for the fine wires after drawing could be eliminated.